Flammable gases, such as natural gas and propane, are typically routed through underground supply lines between buildings and a source of gas, such as a gas main or storage tank, for safety purposes. For several decades, thermoplastic tubing has been the preferred method of making such underground connections, because such plastic tubing eliminates problems with corrosion encountered with the use of metal underground gas piping, in previous times.
Where the plastic gas supply tubing emerges from the ground, for connection to gas meters and regulators, and the like, common sense and government regulations require that a protective sheath, known in the industry as a gas riser, be installed around the plastic gas supply tube, from the point of the above-ground connection, to an underground point on the tube spaced several feet from the above-ground point of connection. The gas riser, therefore, protects the plastic tube from being damaged by contact above-ground with lawnmowers, grass trimmers, and the like, and also provides protection extending along the length of the riser underground.
Although the particular configuration of a given gas riser will be determined by applicable government regulations, and preferences of a particular gas supplier, such risers are generally required to be L-shaped, with a lower leg of the L extending substantially horizontally underground for receiving the plastic tube from the source of the gas, and the second leg extending substantially vertically out of the ground for connection to a gas regulator, meter, or other piping attached to the building being supplied with gas.
In some gas riser installations, regulations and customer preferences dictate that at least a portion of the vertically extending leg of the riser be formed from a rigid section of metal pipe. The remainder of such risers is sometimes provided by a flexible metallic conduit attached to the lower end of the rigid section. In other gas riser applications, the rigid pipe section is eliminated, and the entire riser is formed from a flexible metal conduit material.
The underground end of such gas risers typically includes an environmental seal, having a hole through which the gas supply tubing may pass. The above-ground end of the riser typically includes a threaded fitting, for connecting the riser to a gas meter, regulator, or building piping, in such a manner that the plastic tubing is not exposed.
The L-shape of the installed gas riser makes it difficult to complete the threaded connection to a gas meter, or the like. The entire length of the riser must be rotated about the gas supply tube in order to complete the connection.
In order to facilitate making the above-ground threaded connection of the gas riser to a meter, or the like, various types of swivel fittings have been employed, in the past. In some instances, the swivel fittings are screwed onto, or into, the end of the riser. In other prior approaches, various types of swiveling fittings have been attached directly to the upper end of the riser, by methods which are undesirably complex and cumbersome.
It is desirable, therefore, to provide an improved gas riser. It is particularly desirable to provide an improved gas riser having an integral swivel at the above-ground end thereof, and methods for making and using such an improved riser.